US20050083042A1 - Tandem rotation detector - Google Patents

Tandem rotation detector Download PDF

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Publication number
US20050083042A1
US20050083042A1 US10/950,832 US95083204A US2005083042A1 US 20050083042 A1 US20050083042 A1 US 20050083042A1 US 95083204 A US95083204 A US 95083204A US 2005083042 A1 US2005083042 A1 US 2005083042A1
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US
United States
Prior art keywords
rotation
detection mechanism
rotary shaft
rotation angle
housing
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US10/950,832
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English (en)
Inventor
Mutsumi Matsuura
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Minebea Co Ltd
Original Assignee
Minebea Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Minebea Co Ltd filed Critical Minebea Co Ltd
Assigned to MINEBEA CO. LTD. reassignment MINEBEA CO. LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: MATSUURA, MUTSUMI
Publication of US20050083042A1 publication Critical patent/US20050083042A1/en
Abandoned legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D6/00—Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits
    • B62D6/08—Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits responsive only to driver input torque
    • B62D6/10—Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits responsive only to driver input torque characterised by means for sensing or determining torque
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L3/00—Measuring torque, work, mechanical power, or mechanical efficiency, in general
    • G01L3/02—Rotary-transmission dynamometers
    • G01L3/04—Rotary-transmission dynamometers wherein the torque-transmitting element comprises a torsionally-flexible shaft
    • G01L3/10—Rotary-transmission dynamometers wherein the torque-transmitting element comprises a torsionally-flexible shaft involving electric or magnetic means for indicating
    • G01L3/101—Rotary-transmission dynamometers wherein the torque-transmitting element comprises a torsionally-flexible shaft involving electric or magnetic means for indicating involving magnetic or electromagnetic means
    • G01L3/105—Rotary-transmission dynamometers wherein the torque-transmitting element comprises a torsionally-flexible shaft involving electric or magnetic means for indicating involving magnetic or electromagnetic means involving inductive means
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L3/00—Measuring torque, work, mechanical power, or mechanical efficiency, in general
    • G01L3/02—Rotary-transmission dynamometers
    • G01L3/04—Rotary-transmission dynamometers wherein the torque-transmitting element comprises a torsionally-flexible shaft
    • G01L3/10—Rotary-transmission dynamometers wherein the torque-transmitting element comprises a torsionally-flexible shaft involving electric or magnetic means for indicating
    • G01L3/109—Rotary-transmission dynamometers wherein the torque-transmitting element comprises a torsionally-flexible shaft involving electric or magnetic means for indicating involving measuring phase difference of two signals or pulse trains

Definitions

  • the present invention relates to a tandem rotation detector capable of reducing the influence of leakage flux between rotation angle detection mechanisms so that high-precision detection can be always realized.
  • FIG. 1 shows a sectional side view of a conventional tandem rotation detector.
  • this kind of tandem rotation detector (for example, see Japanese Patent Application Laid-Open No. 2003-098019) is used to detect the rotation angles of rotary shafts.
  • the rotation detector has a rotary shaft 104 A and a rotary shaft 104 B arranged in series in a central portion of a cylindrical housing 101 .
  • a first rotation angle detection mechanism 102 A for detecting the rotation angle of the rotary shaft 104 A, and a second rotation angle detection mechanism 102 B for detecting the rotation angle of the rotary shaft 104 B are arranged inside the housing 101 .
  • a first outer core 110 A and a first stator core 130 A are arranged in parallel on the inner surface of the housing 101 .
  • a first inner core 120 A is mounted on the rotary shaft 104 A so as to face the first outer core 110 A
  • a first rotor core 140 A is mounted on the rotary shaft 104 A so as to face the first stator core 130 A.
  • a coil 111 A is wound on the first outer core 110 A with terminals connected to two outer core pins 112 A placed side by side in the horizontal direction, respectively, through which an AC voltage is applied.
  • a coil 121 A is wound on the first inner core 120 A.
  • Coils 131 A are wound on a plurality of annular stator core teeth 133 A provided around the first stator core 130 A.
  • the coils 131 A have four terminals connected to each other in the X direction (horizontal direction) and the Y direction (vertical direction) respectively, and the four terminals of the coils 131 A are connected to four stator core pins 132 A which are placed side by side in the horizontal direction, respectively.
  • Coils 141 A are wound on a plurality of rotor core teeth 142 A provided on the circumference of the rotary shaft 104 A.
  • the second rotation angle detection mechanism 102 B includes a second outer core 110 B, a second inner core 120 B, a second stator core 130 B, and a second rotor core 140 B to detect the rotation angle of the rotary shaft 104 B. Then, based on the detected rotation angles of the rotary shafts 104 A and 104 B, a difference between both rotation angles can be detected.
  • the conventional tandem rotation detector has the following problems.
  • the conventional tandem rotation detector can detect both the rotation angles of the rotary shafts 104 A and 104 B.
  • the housing 101 is formed from a magnetic material for use in strong magnetic field environments. Therefore, under normal magnetic field environments, any amount of leakage flux 109 A could be produced in a direction along the housing from the first rotation angle detection mechanism 102 A to the second rotation angle detection mechanism 102 B as shown by an arrow so that it might affect the performance of the second rotation angle detection mechanism 102 B in detection of the rotation angle of the rotary shaft 104 B.
  • the leakage flux could also be produced in a direction along the housing from the second rotation angle detection mechanism 102 B to the first rotation angle detection mechanism 102 A so that it might also affect the performance of the first rotation angle detection mechanism 102 A in detection of the rotation angle of the rotary shaft 104 A.
  • a shielding plate can be provided between the first rotation angle detection mechanism 102 A and the second rotation angle detection mechanism 102 B, but only the shielding plate is not enough to prevent the influence of leakage flux. Even in this case, the influence of leakage flux remains to be solved.
  • the present invention has been made in view of the above problems, and it is an object thereof to provide a tandem rotation detector capable of reducing the influence of leakage flux between rotation angle detection mechanisms so that high-precision detection can be always done even under normal magnetic field environments.
  • a tandem rotation detector which includes a first rotation detection mechanism configured to generate a magnetic flux through a coil of a first outer core mounted inside a cylindrical housing for detecting the rotation angle of a rotary shaft arranged in the central portion of the housing. It also includes a second rotation detection mechanism which is placed side by side with the first rotation detection mechanism and configured to generate a magnetic flux through a coil of a second outer core mounted inside the housing for detecting the rotation angle of the rotary shaft.
  • the housing is formed from a nonmagnetic material.
  • a shielding plate is provided between the first rotation detection mechanism and the second rotation detection mechanism.
  • the rotary shaft may comprise two rotary shafts arranged in series.
  • the first rotation detection mechanism and the second rotation detection mechanism detect the rotation angles of the two rotary shafts respectively.
  • the rotary shaft may comprise a single continuous rotary shaft.
  • the first rotation detection mechanism and the second rotation detection mechanism detect a rotation angle difference to detect the rotational torque of the rotary shaft.
  • the tandem rotation detector of the present invention includes the first rotation detection mechanism configured to generate a magnetic flux through the coil of the first outer core provided inside the cylindrical housing for detecting the rotation angle of the rotary shaft arranged in the central portion of the housing, and the second rotation detection mechanism which is placed side by side with the first rotation detection mechanism and configured to generate a magnetic flux through the coil of the second outer core provided inside the housing for detecting the rotation angle of the rotary shaft.
  • the shielding plate is provided between the first rotation detection mechanism and the second rotation detection mechanism, the influence of the leakage flux between the rotation angle detection mechanisms can be further reduced.
  • the first rotation detection mechanism and the second rotation detection mechanism can detect the rotation angles of the two rotary shafts respectively, thereby enabling high-precision detection of the two rotary shafts at all times.
  • the first rotation detection mechanism and the second rotation detection mechanism can detect a rotation angle difference to detect the rotational torque of the rotary shaft, thereby enabling high-precision detection of the rotational torque at all times.
  • FIG. 1 is a sectional side view of a conventional tandem rotation detector
  • FIG. 2 is a sectional side view of a tandem rotation detector according to an embodiment of the present invention.
  • FIG. 3A is a graph showing detection errors of rotation angles of rotary shafts detected by the conventional tandem rotation detector.
  • FIG. 3B is a graph showing detection errors of rotation angles of rotary shafts detected by the tandem rotation detector according to the embodiment of the present invention.
  • FIG. 2 is a sectional side view of a tandem rotation detector according to the embodiment of the present invention.
  • a rotation detector has a rotary shaft 4 A and a rotary shaft 4 B arranged in series in a cylindrical housing 1 .
  • a first rotation angle detection mechanism 2 A for detecting the rotation angle of the rotary shaft 4 A, and a second rotation angle detection mechanism 2 B for detecting the rotation angle of the rotary shaft 4 B are provided inside the housing 1 .
  • a first outer core 10 A and a first stator core 30 A are arranged in parallel.
  • a first inner core 20 A is mounted on the rotary shaft 4 A so as to face the first outer core 10 A
  • a first rotor core 40 A is mounted on the rotary shaft 4 A so as to face the first stator core 30 A.
  • a coil 11 A is wound on the first outer core 10 A.
  • the terminals of the coil 11 A are connected to two outer core pins 12 A which are placed side by side in the horizontal direction, respectively, through which an AC voltage is applied.
  • a coil 21 A is wound on the first inner core 20 A.
  • Coils 31 A are wound on a plurality of stator core teeth 33 A provided around the first stator core 30 A.
  • the coils 31 A have four terminals connected to each other in the X direction (horizontal direction) and the Y direction (vertical direction) respectively, and the four terminals of the coils 31 A are connected to four stator core pins 32 A which are placed side by side in the horizontal direction, respectively.
  • Coils 41 A are wound on a plurality of rotor core teeth 43 A of the first rotor core 40 A.
  • the first rotation angle detection mechanism 2 A when an AC voltage is applied to the first outer core 10 A, a voltage corresponding to a magnetic flux generated via the first inner core 20 A is applied to the first rotor core 40 A so that the first rotor core 40 A and the first stator core 30 A will be magnetically coupled. In other words, a voltage corresponding to the rotation angle of the rotary shaft 4 A is induced into the first stator core 30 A, thereby detecting the rotation angle of the rotary shaft 4 A.
  • the second rotation angle detection mechanism 2 B includes a second outer core 10 B, a second inner core 20 B, a second stator core 30 B, and a second rotor core 40 B to detect the rotation angle of the rotary shaft 4 B.
  • numeral 12 B represents outer core pins to which the respective terminals of a coil 11 B of the second outer core 10 B are connected
  • numeral 32 B represents stator core pins to which the respective terminals of coils wound on the second stator core 30 B are connected.
  • the tandem rotation detector according to the embodiment of the present invention detects the rotation angles of the rotary shafts 4 A and 4 B by applying an AC voltage to the coil 11 A of the first outer core 10 A and the coil 11 B of the second outer core 10 B. Since the housing is formed from a nonmagnetic material such as SUS303, no magnetic flux transmits to the outside of the housing 1 , that is, no leakage flux is produced along the housing 1 , thereby reducing the influence of leakage flux.
  • the tandem rotation detector according to the embodiment of the present invention is used in normal environments, the rotation angles can be detected without the ferromagnetic influence from the outside. Then, based on the detected rotation angles of the rotary shafts 4 A and 4 B, a difference between both rotation angles can be detected. So far as environmental noises have no frequency which is the same as or similar to a frequency of the AC voltage applied to the coil 11 A of the first outer core 10 A and the coil 11 B of the second outer core 10 B, the rotation detector will not be affected by the environmental noises.
  • FIG. 3A shows detection error of the conventional tandem rotation detector
  • FIG. 3B shows detection error of the tandem rotation detector according to the embodiment of the present invention.
  • the tandem rotation detector detects the rotation angles of the rotary shafts 4 A and 4 B (see FIG. 2 ) electrically through the first and second stator cores 30 A and 30 B, and a difference in rotation angle (deg) between the rotary shafts 4 A and 4 B is detected through the first and second stator cores 30 A and 30 B.
  • the conventional tandem rotation detector also detects the rotation angles of the rotary shafts and a difference (deg) therebetween in the same manner.
  • FIG. 3A shows detection errors (min) versus mechanical rotation angle (deg) detected by one of the rotation angle detection mechanisms of the conventional tandem rotation detector, plotting the mechanical rotation angle (deg) on the abscissa and the detection error (arcmin) on the ordinate.
  • 1 minute is ⁇ fraction (1/60) ⁇ of a degree.
  • the conventional tandem rotation detector is affected by a leakage flux 109 A (see FIG. 1 ), and hence detection error ⁇ h represents high values.
  • the detection of the rotation angle is repeated for each angle corresponding to the set number of teeth for stator core teeth 133 A of a first stator core 130 A and that for rotor core teeth 142 A of a first rotor core 140 A shown in FIG. 1 . Therefore, the detection error ⁇ h exhibits a periodic ridge pattern.
  • FIG. 3B shows detection errors (min) versus mechanical rotation angle (deg) detected by one of the rotation angle detection mechanisms of the tandem rotation detector according to the embodiment of the present invention, plotting the mechanical rotation angle (deg) on the abscissa and the detection error (min) on the ordinate.
  • detection error ⁇ i represents very small values within one minute over all the angle range from 0 deg. to 360 deg.
  • the tandem rotation detector according to the embodiment of the present invention repeats the detection of the rotation angle, since the detection error ⁇ i represents very small error values as a whole, the curve of distribution of detection errors becomes flatter with smaller error values than those of the conventional.
  • the tandem rotation detector according to the embodiment of the present invention reduces the influence of leakage flux, the detection error ⁇ i is very small values that are about a half of those of the detection error ⁇ h of the conventional tandem rotation detector, thus enabling high-precision detection at all times.
  • tandem rotation detector reduces the influence of leakage flux between the rotation angle detection mechanisms under normal magnetic field environments, thereby enabling high-precision detection at all times.
  • the tandem rotation detector according to the embodiment of the present invention may be provided with a shielding plate 5 between the first rotation angle detection mechanism 2 A and the second rotation angle detection mechanism 2 B as shown in FIG. 2 so that the influence of leakage flux between the rotation angle detection mechanisms can be further reduced.
  • tandem rotation detector according to the embodiment of the present invention has been described in connection with an embodiment for detecting the rotation angles of the rotary shafts 4 A and 4 B, but the present invention is not limited to such an embodiment.
  • the present invention can be applied to an application in which a single rotary shaft is used instead of the rotary shafts 4 A and 4 B, and the two rotation angle detection mechanisms detect the torque of the single rotary shaft.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Electromagnetism (AREA)
  • Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
  • Transmission And Conversion Of Sensor Element Output (AREA)
US10/950,832 2003-10-17 2004-09-27 Tandem rotation detector Abandoned US20050083042A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2003-357360 2003-10-17
JP2003357360A JP2005121501A (ja) 2003-10-17 2003-10-17 タンデム型回転検出装置

Publications (1)

Publication Number Publication Date
US20050083042A1 true US20050083042A1 (en) 2005-04-21

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US10/950,832 Abandoned US20050083042A1 (en) 2003-10-17 2004-09-27 Tandem rotation detector

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US (1) US20050083042A1 (enrdf_load_stackoverflow)
EP (1) EP1524510A1 (enrdf_load_stackoverflow)
JP (1) JP2005121501A (enrdf_load_stackoverflow)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9057652B2 (en) 2011-02-08 2015-06-16 Jtekt Corporation Torque detecting apparatus

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5652656B2 (ja) * 2011-02-08 2015-01-14 株式会社ジェイテクト トルク検出装置
JP5720935B2 (ja) * 2011-02-08 2015-05-20 株式会社ジェイテクト トルク検出装置
JP5652655B2 (ja) * 2011-02-08 2015-01-14 株式会社ジェイテクト トルク検出装置
WO2019146637A1 (ja) * 2018-01-23 2019-08-01 株式会社アミテック 誘導型回転検出装置

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4724710A (en) * 1986-12-22 1988-02-16 General Motors Corporation Electromagnetic torque sensor for a rotary shaft
US5012169A (en) * 1988-07-20 1991-04-30 Yokogawa Electric Corporation Motor drive system
US5062306A (en) * 1989-04-20 1991-11-05 Kabushiki Kaisha Toyoda Jidoshokki Seisakusho Apparatus for detecting torque of rotating shaft

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3831841B2 (ja) * 2001-09-26 2006-10-11 ミネベア株式会社 高精度トルク測定装置

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4724710A (en) * 1986-12-22 1988-02-16 General Motors Corporation Electromagnetic torque sensor for a rotary shaft
US5012169A (en) * 1988-07-20 1991-04-30 Yokogawa Electric Corporation Motor drive system
US5062306A (en) * 1989-04-20 1991-11-05 Kabushiki Kaisha Toyoda Jidoshokki Seisakusho Apparatus for detecting torque of rotating shaft

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9057652B2 (en) 2011-02-08 2015-06-16 Jtekt Corporation Torque detecting apparatus

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EP1524510A1 (en) 2005-04-20
JP2005121501A (ja) 2005-05-12

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Date Code Title Description
AS Assignment

Owner name: MINEBEA CO. LTD., JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:MATSUURA, MUTSUMI;REEL/FRAME:015421/0212

Effective date: 20040903

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION